With funding from the American Beverage Association, Hill helped design a study that divided approximately 300 adults into two groups: One group would continue drinking diet, and the other group -- referred to in the study as the "water group" -- would go cold turkey. The study was published in the journal Obesity.

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10 reasons to give up diet soda – When taken at face value, diet soda seems like a health-conscious choice. It saves you the 140-plus calories you'd find in a sugary soft drink while still satisfying your urge for something sweet with artificial sweeteners like aspartame, saccharin, and sucralose. But there's more to this chemical cocktail than meets the eye. Health.com: The 25 best diet tricks of all time

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It confuses your body – Artificial sweeteners have more intense flavor than real sugar, so over time products like diet soda dull our senses to naturally sweet foods like fruit, says Brooke Alpert, author of "The Sugar Detox." Even more troubling, these sugar stand-ins have been shown to have the same effect on your body as sugar. "Artificial sweeteners trigger insulin, which sends your body into fat storage mode and leads to weight gain," Alpert says.Health.com: 5 steps to quitting artificial sweeteners

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It could lead to weight gain, not weight loss – Diet soda is calorie-free, but it won't necessarily help you lose weight. Researchers from the University of Texas found that over the course of about a decade, diet soda drinkers had a 70% greater increase in waist circumference compared with non-drinkers.

And get this: participants who slurped down two or more sodas a day experienced a 500% greater increase.

It may increase your risk of type 2 diabetes – Drinking one diet soda a day was associated with a 36% increased risk of metabolic syndrome and diabetes in a University of Minnesota study. Metabolic syndrome describes a cluster of conditions (including high blood pressure, elevated glucose levels, raised cholesterol, and large waist circumference) that put people at high risk for heart disease, stroke, and diabetes, Bjork explains.

It has no nutritional value – When you drink diet soda, you're not taking in any calories -- but you're also not swallowing anything that does your body any good, either. The best no-calorie beverage? Plain old water, says Bjork. "Water is essential for many of our bodily processes, so replacing it with diet soda is a negative thing," she says. If it's the fizziness you crave, try sparkling water. Health.com: 15 big benefits of water

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Its sweetener is linked to headaches – Early studies on aspartame and anecdotal evidence suggests that this artificial sweetener may trigger headaches in some people. "I have several clients who used to suffer from migraines and pinpointed their cause to diet soda," Bjork says.

It'll ruin your smile over time – Excessive soda drinking could leave you looking like a "Breaking Bad" extra, according to a case study published in the journal General Dentistry. The research compared the mouths of a cocaine user, a methamphetamine user, and a habitual diet-soda drinker, and found the same level of tooth erosion in each of them. The culprit here is citric acid, which weakens and destroys tooth enamel over time. Health.com: 20 things that can ruin your smile

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It makes drinking more dangerous – Using diet soda as a low-calorie cocktail mixer has the dangerous effect of getting you drunk faster than sugar-sweetened beverages, according to research from Northern Kentucky University. The study revealed that participants who consumed cocktails mixed with diet drinks had a higher breath alcohol concentration than those who drank alcohol blended with sugared beverages. The researchers believe this is because our bloodstream is able to absorb artificial sweetener more quickly than sugar.Health.com: 6 ways to enjoy cocktails guilt-free

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It's associated with depression – A recent study presented at a the American Academy of Neurology meeting found that over the course of 10 years, people who drank more than four cups or cans of soda a day were 30% more likely to develop depression than those who steered clear of sugary drinks. The correlation held true for both regular and diet drinks, but researchers were sure to note that the risk appeared to be greater for those who primarily drank diet sodas and fruit punches. Although this type of study can't prove cause and effect, its findings are worth considering. Health.com: The 10 most depressing states in the U.S.

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It may be bad for your bones – Women over 60 are already at a greater risk for osteoporosis than men, and Tufts University researchers found that drinking soda, including diet soda, compounds the problem. They discovered that female cola drinkers had nearly 4% lower bone mineral density in their hips than women who didn't drink soda. The research even controlled for the participants' calcium and vitamin D intake. Additionally, a 2006 study published in the American Journal of Clinical Nutrition found that cola intake (all kinds, not just diet) was associated with low bone-mineral density in women.Health.com: 11 foods for healthy bones

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It may hurt your heart – Just one diet soft drink a day could boost your risk of having a vascular event such as stroke, heart attack, or vascular death, according to researchers from the University of Miami and Columbia University. Their study found that diet soda devotees were 43% more likely to have experienced a vascular event than those who drank none. Regular soda drinkers did not appear to have an increased risk of vascular events. Researchers say more studies need to be conducted before definitive conclusions can be made about diet soda's effects on health.This article originally appeared on Health.com.

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EXPAND GALLERY

Both participant groups received intensive coaching on successful techniques for weight loss, including regular feedback on the meals they logged in journals. Participants weighed, on average, just over 200 pounds at the start of the study.

"The results, to us, were not at all surprising," says Hill.

While the typical participant banned from drinking diet sodas lost 9 pounds over 12 weeks, those allowed to continue drinking diet soda lost, on average, 13 pounds in the same time period. That's a 4-pound difference.

Hill says that in his clinical experience, many people who have successfully lost significant weight "are heavy users of noncaloric sweeteners."

But why was the diet soda group more successful? The most likely reason is that this group had the easier task.

Cutting calories and boosting exercise takes a lot of willpower. Trying to simultaneously give up something else you regularly enjoy -- such as diet soda -- taxes your ability to stay the course. Most psychologists agree that our willpower is a limited resource.

So while this study did not track calorie consumption, the group blocked from drinking diet sodas most likely ate (or drank) more calories over the course of the 12-week diet.

Since the study lasted just 12 weeks, it remains to be seen whether artificial sweeteners are beneficial in the long-term, says Susan Swithers, a professor of Behavioral Neuroscience at Purdue University. Swithers authored a report last year that found that diet soda drinkers have the same health issues as those who drink regular soda. It found that people who drink diet soda may be "at increased risk of excessive weight gain, metabolic syndrome, type 2 diabetes, and cardiovascular disease," according to the study.

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"What the prospective studies actually suggest is that if you go out 7 years, 10 years, 15 years, 20 years, the cohorts of individuals who are consuming diet sodas have much worse health outcomes," says Swithers.

Those studies show a correlation, and are not designed to show causation. But some researchers like Swithers suspect artificial sweeteners ultimately increase the desire for sweets.

"Doing these short-term studies that look at weight can't really tell us anything about whether or not these products are contributing to these increased risks," says Swithers. "And it's really hard to look at the (long-term) data and come up with any argument that they're helping."

Hill, who along with four other researchers, designed the study, which was selected for funding by the American Beverage Association from among multiple competing proposals. The American Beverage Association's membership includes numerous Coca-Cola and Pepsi-Cola bottling companies.

"It makes sense that it would have been harder for the water group to adhere to the overall diet than the (artificially-sweetened beverage) group," says Hill.

He added, "The most likely explanation was that having access to drinks with sweet taste helps the (artificially-sweetened beverage) group to adhere better to the behavioral change program."

In short, this study addresses the question of whether a regular diet soda drinker should attempt to kick his or her habit while also attempting to lose weight, not whether we should all drink more diet soda in order to lose weight.

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Artificially-sweetened beverages "are not weight-loss enhancers, so it's not anything in the compounds themselves that are promoting weight loss," says Hill.

Kristi Norton, a regular diet soda drinker before the study began, was assigned to the group that required her to kick the habit. At the time of her CNN interview, she was not aware of the study's findings.

She says she lost 12 pounds during the course of the study, but the real difference is in how she feels.

"I feel like I could 1000% tell the benefit of drinking water only. I felt better, I had more energy, I felt healthier, I just generally felt way better," says Norton. "And I can feel the difference now when I drink a diet drink, I can feel this 'heaviness'."